Comparison of Pb-based and Sn-based perovskite solar cells using SCAPS simulation: optimal efficiency of eco-friendly CsSnI3 devices.

In this study, we employed the one-dimensional solar cell capacitance simulator (SCAPS-1D) software to optimize the performance of Pb-based and Sn-based (Pb-free) all-inorganic perovskites (AIPs) and organic-inorganic perovskites (OIPs) in perovskite solar cell (PSC) structures. Due to the higher stability of AIPs, the performance of PSCs incorporating Cs-based perovskites was compared with that of FA-based perovskites, which are more stable than their MA-based counterparts. The impact of AIPs such as CsPbCl3, CsPbBr3, CsPbI3, CsSnCl3, CsSnBr3, and CsSnI3, as well as including FAPbCl3, FAPbBr3, FAPbI3, FASnCl3, FASnBr3, and FASnI3, was investigated. SnO2 and Cu2O were selected as an inorganic electron transport layer (ETL) and a hole transport layer (HTL), respectively. CsSnBr3, CsSnI3, FASnCl3, and FASnBr3 exhibited higher efficiency compared to their Pb-based counterparts. Additionally, most Cs-based perovskites, excluding CsPbI3, demonstrated better performance relative to their FA counterparts. CsSnI3 AIP device also shows the highest short circuit current density (JSC) of 32.85 mA/cm2, the best power conversion efficiency (PCE) of 16.00%, and the least recombination at the SnO2/CsSnI3 interface. The thickness, doping, and total defect density of CsSnI3 PSC have been systematically investigated and optimized to obtain the PCE of 17.36%. These findings highlight the potential of CsSnI3 PSCs as efficient and environmentally friendly PSCs.

Environmentally stable and rapidly polymerized tin-tannin catalytic system hydroxyethyl cellulose hydrogel for wireless wearable sensing.

In recent years, flexible sensors constructed mainly from hydrogels have played an indispensable role in several fields. However, the traditional hydrogel preparation process involves complex and time-consuming steps and the freezing or volatilization of water in the water gel in extreme environments greatly limits the further use of the sensor. Therefore, an ionic conductive hydrogel (SnHTD) was designed, which was composed of tannic acid (TA), metal ions Sn2+, hydroxyethyl cellulose (HEC), and acrylamide (AM) in a deep eutectic solvent (DES) and water binary solvent. It is worth noting that the gel time is shortened to less than 3 min by introducing the Sn-TA redox system. The addition of DES makes the hydrogel have a wide temperature tolerance range (-20 to 60 °C) and the ability to store for a long time (30 days). The introduction of HEC increased the tensile stress of hydrogel from 140.17 kPa to 219.89 kPa. Additionally, the hydrogel also has high conductivity, repeatable adhesion and UV shielding properties. In general, this research opens up a new way for room temperature polymerization of environmentally resistant hydrogel materials and effectively meets the growing demand for wireless wearable sensing.

[Assessment and Source Analysis of Heavy Metal Pollution in Farmland Soil Around Tin Mine].

Studying the status and source analysis of heavy metal pollution in farmland in typical mining and processing areas is an important prerequisite for promoting farmland soil ecological restoration and farmland protection in concentrated mining areas. In this study, the heavy metal content of farmland soil around a mining area in southwest China was detected, and the pollution status, distribution law, health risks, and sources of heavy metals were studied by using the land accumulation index method, comprehensive pollution index method, kriging interpolation method, health risk assessment method, and PMF receptor model on the sampling data. The results showed that the mean values of eight heavy metals in farmland soil except Ni exceeded the local soil background values, and the results of the ground accumulation index evaluation showed that Cd and Hg were extremely polluted； Pb and As showed medium pollution-heavy pollution； and Cr, Zn, Ni, and Cu were lightly polluted. In the health risk assessment, oral ingestion was the main exposure route posing a health risk to the human body； the main element that constituted non-carcinogenic health risks was As, and the carcinogenic risks were from As and Cd. PMF model analysis showed that the contribution rate of weathering natural sources of iron-bearing ore was 28.02%, and the main factors were Ca and Fe. The contribution rate of agricultural sources was 3.02%, and the main factors were Pb and As. The contribution rate of industrial and atmospheric deposition composite sources was 33.09%, and the main factor was Hg. The contribution rate of the parent material source was 17.27%, and the main factor was Ca. The contribution rate of mining activities such as mining and smelting was 18.60%, and the main factors were Zn and Cd.

Simultaneous indoor radon/thoron and in situ outdoor gamma dose measurements and estimation of annual effective dose in a tin mining area of Jos Plateau, Nigeria.

Radon, a radioactive gas can increase the risk of lung cancer when breathe in. Indoor Rn-222 and Rn-220 concentrations were determined using passive radon monitor in some dwellings in a Sn mining area of Jos Plateau. Outdoor gamma radiation was also measured with a hand-held survey meter. The range of Rn-222 and Rn-220 concentrations was from 7-53 Bq m-3 to 41-267 Bq m-3 with averages of 27 ± 17 and 92 ± 65 Bq m-3, respectively. The mean total effective dose due to Rn-222 + Rn-220 was estimated as 2.84 ± 1.57 mSv y-1. Rn-220 contributed between 50 and 95% to the total annual effective dose. There was no correlation between indoor Rn-220 and Rn-222 concentrations in the dwellings. Outdoor gamma radiation measured was between 0.31 ± 0.06 and 0.62 ± 0.08 µSv h-1, and mean annual effective dose calculated was 1.14 ± 0.21 mSv y-1. It is concluded from this study that thoron should not be neglected in dose assessment.

Experimental toothpastes containing ß-TCP nanoparticles functionalized with fluoride and tin to prevent Erosive Tooth Wear.

OBJECTIVES: The present study aimed to synthesize toothpastes containing Beta- TriCalcium Phosphate (ß-TCP) nanoparticles, functionalized with fluoride and tin, and test their ability to reduce erosive tooth wear (ETW). METHODS: Toothpastes were synthesized with the following active ingredients: 1100 ppm of fluoride (as sodium fluoride, F-), 3500 ppm of tin (as stannous chloride, Sn2+), and 800 ppm of ß-TCP (Sizes a - 20 nm; and b - 100 nm). Enamel specimens were randomly assigned into the following groups (n = 10): 1. Commercial toothpaste; 2. Placebo; 3 F-; 4. F- + ß-TCPa; 5. F- + ß-TCPb; 6. F- + Sn2+; 7. F- + Sn2+ + ß-TCPa and 8. F- + Sn2+ + ß-TCPb. Specimens were subjected to erosion-abrasion cycling. Surface loss (in µm) was measured by optical profilometry. Toothpastes pH and available F- were also assessed. RESULTS: Brushing with placebo toothpaste resulted in higher surface loss than brushing with F- (p = 0.005) and F- + ß-TCPb (p = 0.007); however, there was no difference between F- and F- + ß-TCPb (p = 1.00). Commercial toothpaste showed no difference from Placebo (p = 0.279). The groups F-, F- + ß-TCPa, F- + ß-TCPb, F- + Sn2+, F- + Sn2+ + ß-TCPa and F- + Sn2+ + ß-TCPb were not different from the commercial toothpaste (p > 0.05). Overall, the addition of ß-TCP reduced the amount of available fluoride in the experimental toothpastes. The pH of toothpastes ranged from 4.97 to 6.49. CONCLUSIONS: Although toothpaste containing ß-TCP nanoparticles protected enamel against dental erosion-abrasion, this effect was not superior to the standard fluoride toothpaste (commercial). In addition, the functionalization of ß-TCP nanoparticles with fluoride and tin did not enhance their protective effect. CLINICAL SIGNIFICANCE: Although ß-TCP nanoparticles have some potential to control Erosive Tooth Wear, their incorporation into an experimental toothpaste appears to have a protective effect that is similar to a commercial fluoride toothpaste.

Solution-Processed, Surface-Engineered, Polycrystalline CdSe-SnSe Exhibiting Low Thermal Conductivity.

In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric materials. The process entails a series of critical steps: synthesis, purification, thermal treatments, and consolidation, each playing a pivotal role in determining performance, stability, and reproducibility. We have noticed a need for more comprehensive details for each of the described steps in most published works. Recognizing the significance of detailed synthetic protocols, we describe here the approach used to synthesize and characterize one of the highest-performing polycrystalline p-type SnSe. In particular, we report the synthesis of SnSe particles in water and the subsequent surface treatment with CdSe molecular complexes that yields CdSe-SnSe nanocomposites upon consolidation. Moreover, the surface treatment inhibits grain growth through Zenner pinning of secondary phase CdSe nanoparticles and enhances defect formation at different length scales. The enhanced complexity in the CdSe-SnSe nanocomposite microstructure with respect to SnSe promotes phonon scattering and thereby significantly reduces the thermal conductivity. Such surface engineering provides opportunities in solution processing for introducing and controlling defects, making it possible to optimize the transport properties and attain a high thermoelectric figure of merit.

Comparative investigation of tellurium-doped transition metal nanoparticles (Zn, Sn, Mn): Unveiling their superior photocatalytic and antibacterial activity.

In this study, tellurium-doped and undoped metal oxide nanoparticles (NPs) (ZnO, Mn3O4, SnO2) are compared, and a practical method for their synthesis is presented. Nanocomposites were created using the coprecipitation process, and comparisons between the three material categories under study were made using a range of characterization methods. The produced materials were subjected to structural, morphological, elemental composition, and functional group analyses using XRD, FESEM in combination with EDS, and FTIR. The optical characteristics in terms of cutoff wavelength were evaluated using UV-visible spectroscopy. Catalyzing the breakdown of methylene blue (MB) dye, the isolated nanocomposites demonstrated very consistent behavior when utilized as catalysts. Regarding both doped and undoped ZnO NPs, the maximum percentage of degradation was found to be 98% when exposed to solar Escherichia coli and Staphylococcus aureus, which stand for gram-positive and gram-negative bacteria, respectively, and were chosen as model strains for both groups using the disk diffusion technique in the context of in vitro antibacterial testing. Doped and undoped ZnO NPs exhibited greater antibacterial efficacy, with significant inhibition zones measuring 31.5 and 37.8 mm, compared with other metal oxide NPs.

IrSn Bimetallic Clusters Confined in MFI Zeolites for CO Selective Catalytic Reduction of NOx in the Presence of Excess O2.

We developed a simple strategy for preparing IrSn bimetallic clusters encapsulated in pure silicon zeolites via a one-pot hydrothermal synthesis by using diethylamine as a stabilizing agent. A series of investigations verified that metal species have been confined successfully in the inner of MFI zeolites. IrSn bimetallic cluster catalysts were efficient for the CO selective catalytic reduction of NOx in the presence of excess O2. Furthermore, the 13CO temperature-programmed surface reaction results demonstrated that NO2 and N2O could form when most of the CO was transformed into CO2 and that Sn modification could passivate CO oxidation on the IrSn bimetallic clusters, leading to more reductants that could be used for NOx reduction at high temperatures. Furthermore, SO2 can also influence the NOx conversion by inhibiting the oxidation of CO. This study provides a new strategy for preparing efficient environmental catalysts with a high dispersion of metal species.

Intraindividual Comparison of Dose Reduction and Coronary Calcium Scoring Accuracy Using Kilovolt-independent and Tin Filtration CT Protocols.

Purpose To investigate the ability of kilovolt-independent (hereafter, kV-independent) and tin filter spectral shaping to accurately quantify the coronary artery calcium score (CACS) and radiation dose reductions compared with the standard 120-kV CT protocol. Materials and Methods This prospective, blinded reader study included 201 participants (mean age, 60 years ± 9.8 [SD]; 119 female, 82 male) who underwent standard 120-kV CT and additional kV-independent and tin filter research CT scans from October 2020 to July 2021. Scans were reconstructed using a Qr36f kernel for standard scans and an Sa36f kernel for research scans simulating artificial 120-kV images. CACS, risk categorization, and radiation doses were compared by analyzing data with analysis of variance, Kruskal-Wallis test, Mann-Whitney test, Bland-Altman analysis, Pearson correlations, and κ analysis for agreement. Results There was no evidence of differences in CACS across standard 120-kV, kV-independent, and tin filter scans, with median CACS values of 1 (IQR, 0-48), 0.6 (IQR, 0-58), and 0 (IQR, 0-51), respectively (P = .85). Compared with standard 120-kV scans, kV-independent and tin filter scans showed excellent correlation in CACS values (r = 0.993 and r = 0.999, respectively), with high agreement in CACS risk categorization (κ = 0.95 and κ = 0.93, respectively). Standard 120-kV scans had a mean radiation dose of 2.09 mSv ± 0.84, while kV-independent and tin filter scans reduced it to 1.21 mSv ± 0.85 and 0.26 mSv ± 0.11, cutting doses by 42% and 87%, respectively (P < .001). Conclusion The kV-independent and tin filter research CT acquisition techniques showed excellent agreement and high accuracy in CACS estimation compared with standard 120-kV scans, with large reductions in radiation dose. Keywords: CT, Cardiac, Coronary Arteries, Radiation Safety, Coronary Artery Calcium Score, Radiation Dose Reduction, Low-Dose CT Scan, Tin Filter, kV-Independent Supplemental material is available for this article. © RSNA, 2024.

Multivariate analysis applied to X-ray fluorescence to assess soil contamination pathways: case studies of mass magnetic susceptibility in soils near abandoned coal and W/Sn mines.

Determining the origin and pathways of contaminants in the natural environment is key to informing any mitigation process. The mass magnetic susceptibility of soils allows a rapid method to measure the concentration of magnetic minerals, derived from anthropogenic activities such as mining or industrial processes, i.e., smelting metals (technogenic origin), or from the local bedrock (of geogenic origin). This is especially effective when combined with rapid geochemical analyses of soils. The use of multivariate analysis (MVA) elucidates complex multiple-component relationships between soil geochemistry and magnetic susceptibility. In the case of soil mining sites, X-ray fluorescence (XRF) spectroscopic data of soils contaminated by mine waste shows statistically significant relationships between magnetic susceptibility and some base metal species (e.g., Fe, Pb, Zn, etc.). Here, we show how qualitative and quantitative MVA methodologies can be used to assess soil contamination pathways using mass magnetic susceptibility and XRF spectra of soils near abandoned coal and W/Sn mines (NW Portugal). Principal component analysis (PCA) showed how the first two primary components (PC-1 + PC-2) explained 94% of the sample variability, grouped them according to their geochemistry and magnetic susceptibility in to geogenic and technogenic groups. Regression analyses showed a strong positive correlation (R2 > 0.95) between soil geochemistry and magnetic properties at the local scale. These parameters provided an insight into the multi-element variables that control magnetic susceptibility and indicated the possibility of efficient assessment of potentially contaminated sites through mass-specific soil magnetism.

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens.

Antimicrobial resistance has emerged as a global threat to the treatment of infectious diseases. Antibacterial photodynamic therapy (aPDT) is a promising alternative approach and is highly suitable for the treatment of cutaneous bacterial infections through topical applications. aPDT relies on light-responsive compounds called photosensitizer (PS) dyes, which generate reactive oxygen species (ROS) when induced by light, thereby killing bacterial cells. Despite several previous studies in this area, the molecular details of targeting and cell death mediated by PS dyes are poorly understood. In this study, we further investigate the antibacterial properties of two water-soluble Sn(IV) tetrapyridylporphyrins that were quaternized with methyl and hexyl groups (1 and 2). In this follow-up study, we demonstrate that Sn(IV)-porphyrins can be photoexcited by blue light (a 427 nm LED) and exhibit various levels of bactericidal activity against both Gram-(+) and Gram-(-) strains of bacteria. Using localization studies through fluorescence microscopy, we show that 2 targets the bacterial membrane more effectively than 1 and exhibits comparatively higher aPDT activity. Using multiple fluorescence reporters, we demonstrate that photoactivation of 1 and 2 results in extensive collateral damage to the bacterial cells including DNA cleavage, membrane damage, and delocalization of central systems necessary for bacterial growth and division. In summary, this investigation provides deep insights into the mechanism of bacterial killing mediated by the Sn(IV)-porphyrins. Moreover, our approach offers a new method for evaluating the activity of PS, which may inspire the discovery of new PS with enhanced aPDT activity.

[Determination of 24 elements migration in Yixing clay pottery by inductively coupled plasma mass spectrometry].

OBJECTIVE: To establish an analytical method for determining the migration of 24 elements in Yixing clay pottery in 4% acetic acid simulated solution by inductively coupled plasma mass spectrometry. METHODS: Four types of Yixing clay pottery, including Yixing clay teapot, Yixing clay kettle, Yixing clay pot, and Yixing clay electric stew pot, were immersed in 4% acetic acid as a food simulant for testing. The migration amount of 24 elements in the migration solution was determined using inductively coupled plasma mass spectrometry. RESULTS: Lithium, magnesium, aluminum, iron, and barium elements with a mass concentration of 1000 µg/L; Lead, cadmium, total arsenic, chromium, nickel, copper, vanadium, manganese, antimony, tin, zinc, cobalt, molybdenum, silver, beryllium, thallium, titanium, and strontium elements within 100 µg/L there was a linear relationship within, the r value was between 0.998 739 and 0.999 989. Total mercury at 5.0 µg/L, there was a linear relationship within, the r value of 0.995 056. The detection limit of the elements measured by this method was between 0.5 and 45.0 µg/L, the recovery rate was 80.6%-108.9%, and the relative standard deviation was 1.0%-4.8%(n=6). A total of 32 samples of four types of Yixing clay pottery sold on the market, including teapots, boiling kettles, casseroles, and electric stewing pots, were tested. It was found that the migration of 16 elements, including beryllium, titanium, chromium, nickel, cobalt, zinc, silver, cadmium, antimony, total mercury, thallium, tin, copper, total arsenic, molybdenum, and lead, were lower than the quantitative limit. The element with the highest migration volume teapot was aluminum, magnesium, and barium; The kettle was aluminum and magnesium; Casserole was aluminum, magnesium, and lithium; The electric stew pot was aluminum. CONCLUSION: This method is easy to operate and has high accuracy, providing an effective and feasible detection method for the determination and evaluation of element migration in Yixing clay pottery.

Optimization of synergistic capturing platinum group metals by Fe-Sn and its mechanism.

Platinum group metals (PGMs) are strategic metals. Auto-exhaust catalysts are their main application fields. The recovery of PGMs from spent auto-exhaust catalysts has remarkable economic value and strategic significance. Aiming at the problems of ferrosilicon generation for Fe capturing and subsequent oxygen blowing to remove iron with high energy consumption and heat release, a technology of Fe-Sn synergistic capturing PGMs was proposed. Taking full the advantage of the lower melting point of Fe-Sn alloy (<1200 °C) and its unique affinity for PGMs, the PGMs were captured at approximate 1400 °C with Fe-Sn as the collector. In experiment, 500 g of spent auto-exhaust catalysts were employed to minimize error and approximate industrial production. The mechanism of Fe-Sn synergistic capturing PGMs was elucidated. The generation of Fe-Sn-PGMs alloy lowered the activity of [PGMs] in the system, accelerated the reduction of the PGMs oxides and promoted the alloying of [PGMs]. Therefore, Fe-Sn synergistic capturing PGMs was realized. The inability of Si to enter the alloy phase was confirmed by theoretical calculations, avoiding the generation of ferrosilicon. The effects of basicity, CaF2, m(Fe)/m(Sn) and the amount of collector on capturing PGMs were optimized. Under the optimized conditions (basicity R = 1.1, spent auto-exhaust catalysts 70 wt%, CaO 30 wt%, B2O3 10 wt%, CaF2 7 wt%, m(Fe)/m(Sn) = 1/1 and the collector 15 wt%), the content of PGMs in the slag phase was 2.46 g/t. It is feasible to remove Fe and Sn by oxidation to achieve the purpose of PGMs enrichment. This technology offers guidance on the safe, environmentally sound, and efficient disposal of spent auto-exhaust catalysts, promoting the sustainable development of PGMs.

Analyte Extension Method Validation of Elemental Analysis Manual Method 4.7 for Six Additional Elements, Cobalt (Co), Strontium (Sr), Thallium (Tl), Tin (Sn), Uranium (U), and Vanadium (V).

BACKGROUND: An interlaboratory study was conducted at the U.S. Food and Drug Administration's (FDA) Northeast Food and Feed Laboratory (NFFL) and the Center for Food Safety and Applied Nutrition (CFSAN) with the purpose to expand FDA Elemental Analysis Manual (EAM) method 4.7 (Inductively Coupled Plasma-Mass Spectrometric Determination of Arsenic, Cadmium, Chromium, Lead, Mercury, and Other Elements in Food Using Microwave Assisted Digestion) to include new analytes. OBJECTIVE: The goal of the study was to demonstrate the performance of FDA EAM method 4.7 when analyzing new analytes cobalt (Co), strontium (Sr), thallium (Tl), tin (Sn), uranium (U), and vanadium (V). This analyte extension method validation of EAM 4.7 for six additional elements, Co, Sr, Tl, Sn, U, and V, followed all guidelines for a Level 2 or single-laboratory validation and met all acceptance criteria for analyte extensions as per the Guidelines for the Validation of Chemical Methods. METHOD: As per EAM 4.7, this study followed the procedures and used specified equipment operated under recommended conditions. The analyte extension method validation was performed in accordance with protocol and with no deviations. RESULTS: All quality control (QC) requirements for this analyte extension method validation of EAM 4.7 passed as evidenced by the analytical data. The results presented demonstrate accuracy, linearity, and precision by successful analyses of method blanks, matrix spikes, unfortified test samples, and reference materials. The data analyzed met each of the validation requirements for each analyte in all representative matrixes. CONCLUSIONS: The study showed that the new analytes performed satisfactorily using EAM 4.7 for total acidic extractable elemental analysis of food according to FDA's guidelines. HIGHLIGHTS: The method met or exceeded the performance criteria.

Aqueous Synthesis of Plasmonic Gold-Tin Alloy Nanoparticles.

This protocol describes the synthesis of Au nanoparticle seeds and the subsequent formation of Au-Sn bimetallic nanoparticles. These nanoparticles have potential applications in catalysis, optoelectronics, imaging, and drug delivery. Previously, methods for producing alloy nanoparticles have been time-consuming, require complex reaction conditions, and can have inconsistent results. The outlined protocol first describes the synthesis of approximately 13 nm Au nanoparticle seeds using the Turkevich method. The protocol next describes the reduction of Sn and its incorporation into the Au seeds to generate Au-Sn alloy nanoparticles. The optical and structural characterization of these nanoparticles is described. Optically, prominent localized surface plasmon resonances (LSPRs) are apparent using UV-visible spectroscopy. Structurally, powder X-ray diffraction (XRD) reflects all particles to be less than 20 nm and shows patterns for Au, Sn, and multiple Au-Sn intermetallic phases. Spherical morphology and size distribution are obtained from transmission electron microscopy (TEM) imaging. TEM reveals that after Sn incorporation, the nanoparticles grow to approximately 15 nm in diameter.

Catalytic green synthesis of Tin(IV) oxide nanoparticles for phenolic compounds removal and molecular docking with EGFR tyrosine kinase.

In this study, tin dioxide nanoparticles (SnO2 NPs) were successfully synthesized through an eco-friendly method using basil leaves extract. The fabricated SnO2 NPs demonstrated significant adsorption capabilities for phenol (PHE), p-nitrophenol (P-NP), and p-methoxyphenol (P-MP) from water matrices. Optimal conditions for maximum removal efficiency was determined for each phenolic compound, with PHE showing a remarkable 95% removal at a 3 ppm, 0.20 g of SnO2 NPs, pH 8, and 30 min of agitation at 35 °C. Molecular docking studies unveiled a potential anticancer mechanism, indicating the ability of SnO2 NPs to interact with the epidermal growth factor receptor tyrosine kinase domain and inhibit its activity. The adsorption processes followed pseudo-second order kinetics and Temkin isotherm model, revealing spontaneous, exothermic, and chemisorption-controlled mechanisms. This eco-friendly approach utilizing plant extracts was considered as a valuable tool for nano-sorbent production. The SnO2 NPs not only exhibit promise in water treatment and also demonstrate potential applications in cancer therapy. Characterization techniques including scanning electron microscopy, UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD), and energy-dispersive X-ray spectroscopy (EDAX) provided comprehensive insights into the results.

Development of UV-Vis spectroscopy-based analysis method for determination of tin(IV) in epilobium parviflorum (hoary willowherb) tea using deep eutectic solvent based preconcentration.

In this study, a UV-Vis Spectroscopy-based method was developed for the determination of tin(IV) in epilobium parviflorum tea samples after preconcentration. The preconcentration process was carried out using the liquid-liquid microextraction technique. Before starting the analysis, optimization studies were carried out for the variables likely to affect the experimental results. As a result of the analyzes performed under optimum conditions, the detection limit of our method was calculated as 16.83 µg/L. The percent relative standard deviation value was calculated as 1.25% (n = 8) and linearity was found in the range of 10-1000 µg/L. Recovery experiments were performed on epilobium parviflorum tea samples using the matrix matching method. As a result of the analyzes made on teas belonging to three different brands, recovery results ranging from 92 to 117% were obtained.

Remineralisation of enamel and dentine with stabilised stannous fluoride dentifrices in a randomised cross-over in situ trial.

OBJECTIVES: To compare the remineralisation efficacy and ion bioavailability of two novel SnF2-containing dentifrices in a blinded, cross-over, randomised in situ clinical study. METHODS: Six participants wore removal palatal appliances holding human enamel and dentine blocks with subsurface lesions. Appliances were worn for two treatment periods of 14 consecutive days each, with a one-week washout period in-between. Participants were randomly allocated to rinse with a 1:5 diluted coded slurry of one of two dentifrices containing either 5 % casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) +1100 ppm F as SnF2 [MIPOP], or 1100 ppm F as SnF2 [CT], for 1 min, four times a day. Saliva was collected post-treatment and analysed for tin, calcium, inorganic phosphate and fluoride ions using atomic absorption spectrophotometry and ion chromatography. Enamel and dentine lesions were analysed for percent remineralisation (%R) using transverse microradiography and percent surface microhardness recovery (%SMHR). RESULTS: MIPOP released significantly higher F (3.00 ± 0.27 mM), Ca (15.23 ± 3.23 mM) and Sn (1.18 ± 0.13 mM) into saliva whereas CT released 2.89 ± 0.32 mM F and only 0.84 ± 0.11 mM Ca and 0.28 ± 0.10 mM Sn. MIPOP produced significantly higher %R than CT: 25.6 ± 1.5 % compared to 15.2 ± 0.7 % in enamel, and 33.6 ± 3.1 % compared to 20.6 ± 1.1 % in dentine. Additionally, MIPOP produced significantly higher %SMHR (18.2 ± 7.9 %) compared to CT (4.1 ± 0.6 %). CONCLUSIONS: Both dentifrices promoted remineralisation, but the MIPOP dentifrice with added CPP-ACP and the ion-stabilising effects of CPP released higher amounts of bioavailable tin and produced significantly higher remineralisation and surface microhardness recovery. CLINICAL SIGNIFICANCE: Modern dentifrices contain SnF2 for a range of oral health benefits. Challenges associated with stability of these formulations can affect ion bioavailability, reducing efficacy. Two dentifrices with SnF2 promoted remineralisation in situ, however the dentifrice with the added saliva biomimetic CPP-ACP was superior and therefore may produce greater health benefits.

Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection.

OBJECTIVES: To assess the effect of different tin-containing toothpastes on the control of erosive tooth wear in enamel and dentin. METHODS: Enamel and dentin slabs were randomly distributed into 7 experimental groups (n = 10/substrate): C-: negative control (Artificial saliva); AmF (regular fluoridated toothpaste without tin); Sn-1 (SnF2/NaF); Sn-2 (SnF2/NaF/SnCl2); Sn-3 (SnCl2/NaF); Sn-4 (SnF2/SnCl2); Sn-5 (SnCl2/AmF/NaF/chitosan). Specimens were submitted to 5-day erosion-abrasion cycling. Surface loss (SL) was determined with an optical profilometer. Tin deposition on the tooth surfaces and some characteristics of the toothpastes (pH, potentially available F-, %weight of solid particles, and RDA) were also assessed. Data were statistically analyzed (α = 0.05). RESULTS: For enamel, the Sn-2 presented the lowest SL, not differing significantly from AmF, C+, and Sn-3. The SL of these groups was significantly lower than the C-, except for Sn-3. Sn-1 and Sn-4 were also not significantly different from C-. For dentin, C- significantly showed the highest SL values, whilst, Sn-1 presented the lowest SL, not differing significantly from AmF, Sn-2, C+, and Sn-3. There was a significant positive association between enamel SL and the pH and tin deposition. Dentin SL was significantly negatively associated with the %weight of solid particles and RDA. CONCLUSIONS: Most of the tin-toothpastes were able to exhibit some protection against ETW. In this process, the toothpastes characteristics play a role, as lower enamel SL was significantly associated with lower pH values and tin deposition; and lower dentin SL was associated with higher %weight of solid particles and RDA of the toothpastes. CLINICAL SIGNIFICANCE: Tin-containing toothpastes can be used for erosive tooth wear protection, but our study showed that their effect depends on the pH, amount of tin deposition, % weight of solid particles and RDA of the toohpastes.

Influence of spectral shaping and tube voltage modulation in ultralow-dose computed tomography of the abdomen.

PURPOSE: Unenhanced abdominal CT constitutes the diagnostic standard of care in suspected urolithiasis. Aiming to identify potential for radiation dose reduction in this frequent imaging task, this experimental study compares the effect of spectral shaping and tube voltage modulation on image quality. METHODS: Using a third-generation dual-source CT, eight cadaveric specimens were scanned with varying tube voltage settings with and without tin filter application (Sn 150, Sn 100, 120, 100, and 80 kVp) at three dose levels (3 mGy: standard; 1 mGy: low; 0.5 mGy: ultralow). Image quality was assessed quantitatively by calculation of signal-to-noise ratios (SNR) for various tissues (spleen, kidney, trabecular bone, fat) and subjectively by three independent radiologists based on a seven-point rating scale (7 = excellent; 1 = very poor). RESULTS: Irrespective of dose level, Sn 100 kVp resulted in the highest SNR of all tube voltage settings. In direct comparison to Sn 150 kVp, superior SNR was ascertained for spleen (p ≤ 0.004) and kidney tissue (p ≤ 0.009). In ultralow-dose scans, subjective image quality of Sn 100 kVp (median score 3; interquartile range 3-3) was higher compared with conventional imaging at 120 kVp (2; 2-2), 100 kVp (1; 1-2), and 80 kVp (1; 1-1) (all p < 0.001). Indicated by an intraclass correlation coefficient of 0.945 (95% confidence interval: 0.927-0.960), interrater reliability was excellent. CONCLUSIONS: In abdominal CT with maximised dose reduction, tin prefiltration at 100 kVp allows for superior image quality over Sn 150 kVp and conventional imaging without spectral shaping.